Severe Hand and burning Back pain.

10 months history of hand and back pain with severe loss of function. Burning, nerve-like pain in wrist and fingers (especially thumb side), extending in a line along forearm to elbow and sometimes shoulder. Triggered by typing, writing, or phone use. Initially right-sided, now present on left as well. Feels like irritation and perceived weakness in grip. Severe one-sided back pain with inability to sit for more than a few minutes. Pain increases with sitting and improves with lying or changing position. Difficulty bending, squatting, or maintaining posture. History of prolonged asymmetric sitting posture. Significant activity reduction over months. Vitamin D deficiency (18.4) and low B12 (~200) treated 3 months ago. Unable to study, work, or use laptop. Need diagnosis and 7-day plan to regain function.